In most mouse species, males maintain separate territories from females, so they encounter female urine only occasionally, and then they respond with great interest. (sciencedaily.com)
When placed in a box with light and dark compartments, most mice tend to seek refuge in the dark sections — but not the germ - free mice. (sciencemag.org)
Imagine an island where most mice are plain but a few have stripes. (newscientist.com)